Peak ground velocity, or PGV, refers to the maximum horizontal velocity of the ground during an earthquake. There are several synonyms for this term, including peak ground acceleration (PGA), which refers to the maximum rate of change of velocity during an earthquake, and peak ground displacement (PGD), which measures the maximum displacement of the ground during an earthquake. Other synonyms for PGV include peak horizontal acceleration (PHA), peak horizontal velocity (PHV), and peak ground motion (PGM). These terms are all used to describe different aspects of seismic activity and are essential for measuring and predicting the effects of earthquakes on infrastructure and populations.